R.e. 1991 mk2 8v Golf GTi + Cat convertor query..?

[theombudsman]

Hi All...

This is my first post on the forum, regarding my mk2 Golf Gti 8 valver... (after a year of getting used to  it after selling my mk1 campaign and really loving it... great car..!)

Anyways on to my query... Am hoping that someone can help me with some advice about a prob have got with the car. My standard exhaust with the twin rear pipes is starting to sound a bit agricultural now and somewhere along it needs replacing... trouble is I have got a late 1991 car with the digifant + cat convertor, which I gather does the car no favours and unnecessarily blunts its standard performance potential compared to earlier versions..

Was wondering if it is at all possible (with out spending silly amounts of money) to revert the set up to a pre cat version, i.e take the cat convertor off and have some sort of straight through pipe.

I have had a few conversations with people and am left not really knowing what can be done. have been told there is a sensor in the exhaust that reads the levels. Also there is some sort of computer type thing in the engine somewhere that would cause the engine to malfunction if I took the cat off....

Well I am getting right confused,,, my lovely car is sounding like a Massey Ferguson and I have not a great deal of wedge to throw at the this problem. Would like to get rid of the Cat as am sure it would make quite a difference top to the performance. My old mk1 Gti had none of this tomfoolery aboard and sure was a more lively performer. ( I do understand that the mk2 is heavier than a mk1 so would not expect it to be the same)

Sorry for the long rambling query... any help and advice will be greatly appreciated. Would like to get this sorted out as soon as... Cheers

Adam ( Wells, Somerset)

P.S. One other general question... do mk2 golf gti 8 valvers have less water repellent engines than the mk1 gti's for some reason? Mine does not like wet wintery roads very much... the mk1 I had seemed like you could drive it through a lake and it would'nt grumble much... wondering if some water is coming in somewhere it shouldn't.

[Zoid]

Just did a quick search on the emissions laws and read this...

"Vehicles fitted with catalysts and first used before 1st August 1992 are not subject to the catalyst emissions test."

So you should be able to simply have the cat removed and fit a standard exhaust, as far as I'm aware it should be very simple to do and gain you about 5bhp.

[theombudsman]

Hi Zoid,

Thanks for the quick reply. Nice car aswell... good to see it standard.. is that a helios blue one or whatever the colour is called?

That info sounds promising... thanks. Am still concerned about the emissions sensors and computer thing tho. I have looked in the Haynes manual and it shows a part called a TCI-H controller / chip device with a big plug coming off it that connects into the cat system via the distributor, by the looks of it. This is situated in the scuttle under the windscreen, drivers side. 

That would be great if I could just put a standard exhaust part on (part that is blowing) and remove the cat.

Cheers,

Adam

[Veedubgt18v]

the only sensor in the exhaust i can think of would be a lambda sensor to measure oxygen in the exhaust gas so the ecu can determine if the car is overfuelling or running lean. im pretty sure you would be able to get a replacement pipe with a threaded hole in it to mount this sensor. is what is weird is i have a 1992 8v and have no cat pipe or sensor! you sure its a catalytic converter? sorry not taking the piss just asking! you should have a backbox then a cylindrical front silencer in about the middle of the car. i think 16v's have 3 boxes.

hope this helps!

but yeah take it off!

ed

[theombudsman]

Hi

thanks for your reply... yeah its one of those rare collectors item features that not that keen on having there.

It definetly does have one as there is a vw sticker on the cylinder head about cat / oil stuff. Have had it on a ramp too, cat pipe sits just forward from the straight section after the downpipe levels out

Odd huh.... the puzzle continues.

Cheers

Adam

[Gambit]

aye it was an optional extra (an expensive one at that!!) for those worried about the environment

[elnigel]

Hi mate, ive got an 89 pre cat digifant, it has no sensor on the exhaust. so therefore why dont you try getting a downpipe like mine without lamda probe in it and an ecu from an early digifant like mine, as this wont rely on info from a lamda probe as its not got one. should be able to get an ecu from breakers or ebay for ?20.

Just an idea

[...joe]

or even better, get a g60 down pipe and buy a cat replacement pipe. this way you keep the lambda probe and get a larger bore downpipe to help shift thoses gases? then with the cat replacement you free up the airflow even more.

[Veedubgt18v]

gtijoe i like the way you think...............

if it breaks uprate it! 

[...joe]

^^thats my philosophy!!